This invention relates to programmable control systems that control gas or liquid dispensing devices. More particularly, the present invention relates to programmable heating, ventilating and air conditioning control (HVAC) systems, and to programmable water control systems for controlling the operation of a plurality of plumbing fixtures, such as showers, sinks, toilets, sprinklers and the like.
Control systems are known that control a plurality of gas dispensing devices such as heaters, ventilators, and air conditioners in an HVAC system. Water control systems are also known that control a plurality of water dispensing devices, such as sprinklers, sinks, showers, toilets and the like. A typical water control system has a controller that controls the operation of one or more solenoid valves. In general, each valve controls the water flow to at least one water dispensing device. The time at which one or more valves is to be turned ON, the length of the ON time of a particular fixture or group of fixtures, any designated OFF times for the fixtures, and the number of operations of a fixture during a predetermined time period may be either preprogrammed or input via an input device such as a keypad. The controller receives the input information and controls the operation of the associated valves to implement the instructions.
Although the duration of fixture operation may be readily changed, the manner or mode in which the fixture operates typically cannot be changed in prior art control systems. That is, the mode or "personality" of the fixture and its operation is predetermined because the fixture's controller is typically a dedicated processor. The only way to change the fixture's mode of operation--other than the duration and timing of its operation--is to replace the controller altogether.
For example, assume that a controller controls several water dispensing devices of a first type, such as a group of showers. Although the duration of shower operation, the number of operations per unit time, and any periods when the showers are prevented from operating (called "block-out" times) may be changed, the controller is a dedicated shower controller. It cannot also be used to control toilets, faucets, or other types of water dispensing units since these units have much different timing requirements. For example, a shower may be set to operate both hot and cold water valves for five minutes each, but a toilet only uses cold water and only flushes for a few seconds. Thus, a separate dedicated controller having different programmed instructions and different circuitry would be needed to control the toilet. Similarly, a different type of controller would be needed to control the faucet operation as well.
This requirement for several different types of controllers and programming instructions results in a water control system which is very expensive where more than one type of water dispensing unit is being controlled. In a prison system, for example, distinct controllers and/or software programs must be used to control the toilets, the sinks, and the showers for each group of cells. Also, the controller for the toilets cannot be used to control the showers.
A related disadvantage of prior art systems is that once the mode of a particular water dispensing fixture has been preset, it cannot be changed without replacing the controller or rewriting the software. For example, one mode of operating a shower is a "meter-only" mode. When the user presses a button, the metering or ON cycle begins. The cycle runs its full course for the preset time even if the button is pushed again. Once the showers have been installed in a meter-only mode, the mode cannot be changed. However, the proprietor of the facility may later wish to change the shower mode to a "double-touch" mode in which one touch of the button starts the cycle, and a second touch of the button ends the cycle even if the cycle is not completed. In a typical prior art water control system, this mode could only be changed by replacing the entire controller or by re-writing the software which operates the controller.
Since prior art water control systems have only a single controller, the mode of all the showers would have to be changed. That is, there is no provision for changing the mode of only a single group of showers without changing the mode for all of the showers. Even if the mode is to be changed, the water and/or the power must typically be shut off to the system to make the change, resulting in down time.
Since the prior art control systems have hardware or software which is not readily changed, the system cannot be used in different types of applications without redesigning the circuitry or rewriting the software. For example, a water control system for a prison cannot be readily adapted to control the restrooms in an office building. This limitation of prior art systems increases the cost of the systems since additional engineering time is needed to redesign the system for different applications.